Sofa



FIG. 1 is a front perspective view of a sofa showing my design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a back view thereof; and,

FIG. 4 is a side perspective view thereof, an opposite side perspective view being a mirror image thereof.

The broken lines shown on the sofa are understood to represent stitching. The dot-dashed lines shown in the drawings are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a sofa, as shown and described. 